Coaxial and shielded in-line termination



July 18, 1967 M. F. OKEEFE ETAL 3,331,917

COAXIAL AND SHIELDED IN-LINE TERMINATION Filed March 10, 1965 2Sheets-$heet 1 2 INVENTOR.

All AND SAMUEL APA Jul 18,1967 O'KEEFE ETAL 3,331,917

COAXIAL AND SHIELDED IN-LINE TERMINATION Filed March 10, 1965 2Sheets-Sheet 2 INVENTOR. ARMMuv SAMUEL APA MICHAEL Frumus O'KeEFe BY Mhum S fib-uL United States Patent Filed Mar. 10, 1965, Ser. No. 438,493Claims. (Cl. 174-75) ABSTRACT OF THE DISCLOSURE A coaxial or shieldedcable terminal is disclosed which includes an in-line termination ofinner and outer cable conductors through a structure including an innerbody of insulating material containing a spring contact member for cableinner conductors and having positioned outwardly on the ends thereofrigid deformation resilient rings against which the cable outerconductor is forced by a thin malleable outer ferrule which extendsalong the length of the body. The inner contact insulating body anddeformation resistant rings are covered over by a sleeve of insulatingmaterial made to extend out over the cable and an outer protectivesheath thereof and ferrules are provided on each end of theouter sleeveto be crimped inwardly to seal all of the conductive metallic partsagainst the environment of use.

Background of the invention In-line terminals and splices are well-knownand a wide variety of constructions are available. Most existing unitshowever, either provide no sealing or include a relatively large numberof loose pieces requiring a relatively time consuming assembly procedureand requiring a series of separately applied crimps of differentgeometries applied by different tools or by differently shaped dies inthe same tool.

Summary of the invention This invention relates to an assembly ofconductive and insulating elements adapted to be crimped or otherwisedeformed to provide a sealed splice or termination of coaxial andshielded cable.

It is one object of the invention to provide a sealed terminal forcoaxial or shielded cable which is of a unitary construction so arrangedas to permit crimping in one stroke. A further object is to provide anin-line termination of coaxial and shielded cable which effectivelyseals the conductors terminated against the environment of use,particularly moisture. It is still another object to provide an in-linesplice for mechanically and electrically joining the ends of coaxial orshielded cable in a manner to provide superior electricalcharacteristics and strength. It is a further object to provide a splicefor mechanically and electrically joining the ends of coaxial or braidedcable wherein only the outer conductor or braid of the cable need beterminated by deforming a ferrule thereover, the center conductors beingaccommodated by axial insertion into a resilient receptacle.

The foregoing objects are obtained through the invention in itsapplication as a termination through the use of first and second ferrulemembers disposed respectively adjacent to the braid or cable outerconductor beneath and outside of an insulating sleeve which fits overthe cable outer protective sheath. The ferrule members are axiallyspaced apart and are of diameters differing by the insulating sleevethickness. The invention in its aspect as a splice includes thetermination feature just described at either end of a continuousstructure having a center dielectric insert carrying a double-endedSpring receptacle into which the cable center conductors are forced forthe purposes of effecting an electrical union therebetween. In thesplice embodiment the ferrule members adapted to terminate the braid arecommon and in all embodiments the ferrule members are of relatively thinmetallic material so as to be readily deformable.

In the drawings:

FIGURE 1 is a perspective of the invention unit in the form of anin-line splice prior to insertion of cables therein and deformation;

FIGURE 2 is a longitudinal section of an in-line splice embodiment ofthe invention having one end terminated to coaxial cable and the otherend undeformed with the cable prepared and in position for insertiontherein; and

FIGURE 3 is an exploded View of the in-line splice embodiment of theinvention showing separately the various parts thereof prior to assemblystaking or final deformation.

The drawing figures are enlarged about four times from the actual sizeof an in-llne splice adapted for use with type RG-59/U shielded cable.The cable shown in FIGURE 2 includes a center conductor 2, a dielectricsheath 4, braid 6 and an outer protective sheath 8. The in-line splicedepicted as unit 10 is comprised of a plurality of elements mechanicallyheld together to form essentially one-piece which may be sold, shippedand handled as such without requiring assembly of a number of loosepieces. To utilize the unit 10, one need only prepare the coaxial orshielded cable in a manner indicated to the left of FIGURE 2 and insertthe prepared end of the cable within the assembly. Thereafter, forreasons hereinafter to be given, the cable will be frictionally heldwithin the splice so that controlled deformation of the ferrule membersmay be accomplished to perfect termination of the cable. The unit shownrelates to a specific embodiment of the invention in the form of anin-line splice, but it is contemplated that as a part of the inventionthe termination performed on the outer end may be employed with a widevariety of constructions such as connectors, junctions and the likewherein the inner end would be replaced with a structure having threadedor bayonet-type fittings or a mounting flange. The invention ascontemplated then relates to both a terminal and a splice.

Description of a preferred embodiment of the invention Looking now atthe various elements of unit 10, the characteristics and structuralrelation thereof, reference is made to FIGURES l and 3 showingrespectively, the assembly of the various elements and the elementsprior to assembly. Beginning at the bottom of FIGURE 3 there is includedas an integral structure, an insulating and protecting sleeve 12 whichin an actual unit was made of polyvinyl chloride tubing sufficientlysoft to permit the unique crimping operation to be hereinafterdescribed. Prior to assembly of unit 10 the sleeve 12 is as shown inFIGURE 3, cylindrical along its length. After assembly the sleeveincludes a pair of humps 12a axially spaced apart near but not at theends of the sleeve. Fitted inside of 12 is a metallic sleeve 14 which isof a length to extend over a substantial portion of the length of 12.The sleeve 14 after insertion with 12 is deformed at each end to providea turned portion 14a, forming a slight flange ex tending radiallyoutwardly and a rounded and smooth entry extending inwardly. Afterinsertion of the dielectric insert within sleeve 14, the sleeve isdeformed circumferentially to form a ridge reducing the bore of 14 inthe center thereof, indicated as 14b in FIGURE 2. In an actualembodiment the sleeve 14 was made ofthin tin-plated copper suitablysoftened by annealing to permit deformation at the ends thereof forcrimping purposes. As will become apparent, sleeve 14 serves both as aferrule and as a splice strengthening member. Sleeve 14 is positionedWithin 12 in the manner indicated in FIGURE 1 and the end turnedportions 1411 are dimensioned to deform the sleeve 14 outwardly todevelop the humps 12a with the outward flange serving to lock the piecestogether.

Fitted within sleeve 14 is aninsert 16 of dielectric material which hasa center cylindrical portion 16a relieved as at 16b to cooperate withthe indentation formed by 145 and lock the insert within 14. At each endof the cylindrical portion 16a is a further cylindrical portion 16cterminating in a flange portion 16d which is beveled on its outersurface and is perpendicular on its inner surface. Within 160 is a bore16:: of a diameter approximately but slightly larger than the dielectricsheath of the cable to be terminated. At the inner end of bore 16c is ashoulder 16f sloped inwardly and relieved as at 16g to guide the cablecenter conductor within the splice as it is inserted. Extending fullythrough the insert between bores 16:: is a bore 16h adapted to receive acenter contact member.

Over the outside of sleeve portions 16c are fitted sleeve members 18which are axially forced thereon over the beveled outer surface of 16d.The sleeve members 18 are of a length to nest between the transitionsurface of the insert and the inner end of 160 and the inner verticalsurface of portion 16d in the manner shown in FIGURE 2. The thicknessand material characteristics of member 18 are such as resist deformationunder crimping forces applied radially inwardly to the portions of 14diposed over the sleeves 18. At the outer end of the sleeves there is abeveled portion 18a which mates with the beveled portion of 16d toprovide a continuous surface engaged by the outer conductor or braid ofthe cable upon insertion. As shown in FIGURE 2 the cable braid is guidedthereby outside and over the surface of the sleeve 18 and within 14, theflaring at 14a assisting. The serrations 18b extending around and overthe outside of 18 are provided to contact the braid or outer conductorof the cable and operate during crimping to drive the braid materialinto the material of 12 to assure a good interface of clean metal in theZone of termination.

Within insert 16 as shown in FIGURE 2 in position and in FIGURE 3 inperspective, as a one-piece contact member 20 which is sleeve-like inthe center, with spring portions 20a formed at each end, around thecenter of 20- is a slight indentation 20b which operates to limit theinsert of the cable center conductors. The outside diameter of 20relative to the bore 16h, is such that the contact is wedge-fittedwithin the insert to resist axial displacement. Member 20 is made ofconductive material having spring characteristics and the outer ends ofthe spring portion 20a are beveled as at 200 to facilitate entry of thecable center conductor.

To complete the unit 10, a pair of ferrules 22 are provided which are ofmalleable material and of a thickness to permit the deformationindicated in FIGURE 2 at the right-hand side thereof. The inner diameterof each is dimensioned to match the outer diameter of sleeve 12 in itsrelaxed state so that the ferrules 22 may be fitted thereover andpositioned inwardly to a point of engagement with the humps 1211.Thereafter, the ferrules are locked on 12 by dimples 22a disposed atseveral points around the ferrule periphery which is just sufficient tohold the ferrules in place.

In use the cable is prepared as shown in FIGURE 2 and inserted withinthe end of assembly 10; the center conductor shown as 2 being positionedand forced within" the spring portions of the member 20, the dielectricshown as 4, fitting within the bore 16a of the insert and the braid orouter conductor 6 being guided out over 18 and under the outer portionsof 14. The preparation of the cable is such as to leave the outerinsulating and protective sheath 8 continuous for a length so that asthe cable is inserted the sheath extends well within 12 and fully under22.

With the cable so inserted the unit 10 is then deformed with one crimpbeing applied to 22 over 12 to drive such inwardly and another crimpbeing applied directly to 12 over 18 to deform portions of 14. It isgenerally preferred that circular crimps be applied in both instances. Adescription of one preferred type is given in US. Patent No. 3,010,184to Edgar W. Forney, J r.

The spring of ferrule 22 relative to the entry of the cable and inconjunction with the sleeve 12, which is somewhat flexible, operate topermit bending loads on the cable without straining the contactinterfaces within the unit. Additionally, sudden axial loads applied tothe cable are accommodated by the resiliency of the sleeve 12 and theclamping thereof by 22 spaced outwardly of the connector of the cableouter conductor.

In applications wherein the termination and splice of the invention areutilized for higher frequency signals the insert with respect todimension and dielectric constant may be based upon calculations toprovide a substantially matched impedance along its length in thepresence of conductive path diameter changes.

The foregoing description is intended to serve as a disclosure of apreferred mode of practicing the invention, which is now claimed.

What is claimed is:

1. In a terminal for coaxial or shielded cable of the type having aninner conductor surrounded by a dielectric sheath, an outer conductorand a protective sheath, the combination comprising a centrally disposedbody of dielectric material having a bore adapted to accommodate theinsertion of the cable dielectric sheath and inner conductor, a contactmember secured in said bore adapted to receive the cable innerconductor, an end portion of said body having an outer diameter slightlylarger than that of the diameter of the cable outer conductor and lessthan the outer diameter of the said body adjacent said end portion withthe outer end of said end portion being beveled inwardly to guide saidouter conductor thereover during installation, a hard deformationresistant ring fitted over said end portion and aflixed thereto, saidring having an axial length slightly less than that of said end portionand a maximum outer diameter approximately equal to that of the end ofsaid end portion and a thin malleable conductive sleeve member extendingover said body, said end portion and said ring, the sleeve member havingan inner diameter sufficiently greater than said ring to accommodate thevolume of said cable outer conductor when inserted therewithin over saidring and adapted to be deformed inwardly to drive said cable outerconductor inwardly against said ring to terminate said outer conductorto said sleeve member inner surface, the said sleeve member and ringhaving material characteristics relative to each other wherebydeformation of said sleeve to terminate said cable outer conductor tosaid sleeve member may be achieved without changing the inner diameterof said ring.

2. The terminal of claim 1 wherein there is included an outer insulatingsleeve surrounding said conductive sleeve member and extendingtherealong and outwardly over the end thereof, said insulating sleevehaving an inner diameter along its length approximating the outerdiameter of said conductive sleeve member, a thin malleable ferrulepositioned on said outer insulating sleeve on the portion thereofextending beyond said conductive sleeve member, said insulating sleevehaving a thickness and material characteristics to permit deformation ofsaid conductive sleeve member through said insulating sleeve and to bedeformed into a sealing engagement with the dielectric sheath of saidcable upon deformation of said ferrule positionedthereon.

3. The terminal of claim 2 wherein said insulating sleeve extendsaxially outward of said conductive sleeve and has an inner diameterextending for a substantial length to accommodate the cable protectivesheath and there is included a further sleeve positioned around saidinsulating sleeve at a position axially spaced from said conductivesleeve, said further sleeve being adapted to be deformed inwardly todrive said insulating sleeve into a tight gripping relationship with thecable insulating sheath.

4. In a terminal for coaxial or shielded cable of the type having acenter conductor surrounded by a dielectric sheath, an outer conductorand an outer protective sheath, the combination comprising a body ofdielectric and insulating material including a first central bore, acontact member disposed in said bore adapted to receive the cable centerconductor, a second bore in said body axially aligned with said firstbore and of a larger diameter to accommodate and support the dielectricsheath of said cable to 'be inserted therein, the body portionsurrounding said second bore being of a reduced wall thickness, a firstmetallic sleeve of rigid deformation resistant material disposed aroundand extending along the portion of said body overlying said second bore,a second metallic sleeve of thin malleable material secured to said bodyand extending over said body and over said first metallic sleeve, theinterior of said second sleeve being spaced from said first sleeve by anamount sufficient to accommodate the insertion of the cable outerconductor, an insulating sleeve surrounding said second sleeve andextending thereover axially outwardly of said first and second sleeves,a third metallic sleeve disposed over said insulating sleeve toward theouter end thereof and adapted to be deformed inwardly to hold theinsulating sleeve material inwardly against the outer protective sheathof said cable whereby to seal the forward contact portion of saidtermination against contaminants and to provide a flexible support ofsaid cable at a point axially spaced from the entry of the outer andinner conductors in the area of termination.

5. The terminal assembly of claim 4 wherein said first metallic sleeveis staked to said body against axial displacement relative thereto, saidportion of said body of reduced wall thickness includes an outer flangeengaging an end, surface of said second sleeve to hold such againstaxial displacement relative to said body and the said third ferrule issecured to said outer insulating sleeve against axial displacement.

6. The terminal of claim 4 wherein the outer diameter of said firstsleeve is approximately equal to the inner diameter of the third sleeveplus twice the wall thickness of said insulating sleeve.

7. The terminal assembly of claim 4 wherein the outer end of the bodyportion of reduced wall thickness and the outer end of the second sleeveare shaped in a complementary angle and engaged to provide asubstantially continuous bevel tending to guide the outer conductor ofsaid cable outwardly and over said second sleeve.

8. The terminal assembly of claim 7 wherein the outer end of said firstsleeve is spaced axially outwardly of the outer end of said secondsleeve.

9. The terminal assembly of claim 8 wherein the outer end of said firstsleeve is rounded in an outward sense to guide the ends of the cableouter conductor upon insertion inwardly to slide between said firstsleeve and said second sleeve.

10. The terminal assembly of claim 9 wherein the outer end of said firstsleeve includes an outwardly directed flange portion adapted to deformsaid insulating sleeve to develop an annular outward deformationlimiting insertion of said third sleeve onto said insulating member.

References Cited UNITED STATES PATENTS 2,774,810 12/1956 Ritter 174-90 X2,904,609 9/1959 Forney 17488 3,147,057 9/1964 Colussi 17488 X DARRELLL. CLAY, Primary Examiner.

1. IN A TERMINAL FOR COAXIAL OR SHIELDED CABLE OF THE TYPE HAVING ANINNER CONDUCTOR SURROUNDED BY A DIELECTRIC SHEATH, AN OUTER CONDUCTORAND A PROTECTIVE SHEATH, THE COMBINATION COMPRISING A CENTRALLY DISPOSEDBODY OF DIELECTRIC MATERIAL HAVING A BORE ADAPTED TO ACCOMMODATE THEINSERTION OF THE CABLE DIELECTRIC SHEATH AND INNER CONDUCTOR, A CONTACTMEMBER SECURED IN SAID BORE ADAPTED TO RECEIVE THE CABLE INNERCONDUCTOR, AN END PORTION OF SAID BODY HAVING AN OUTER DIAMETER SLIGHTLYLARGER THAN THAT OF THE DIAMETER OF THE CABLE OUTER CONDUCTOR AND LESSTHAN THE OUTER DIAMETER OF SAID BODY ADJACENT SAID END PORTION WITH THEOUTER END OF SAID END PORTION BEING BEVELED INWARDLY TO GUIDE SAID OUTERCONDUCTOR THEREOVER DURING INSTALLATION, A HARD DEFORMATION RESISTANTRING FITTED OVER SAID END PORTION AND AFFIXED THERETO, SAID RING HAVINGAN AXIAL LENGTH SLIGHTLY LESS THAN THAT OF SAID END PORTION AND AMAXIMUM OUTER DIAMETER APPROXIMATELY EQUAL TO THAT OF THE END OF SAIDEND PORTION AND A THIN MALLEABLE CONDUCTIVE SLEEVE MEMBER EXTENDING OVERSAID BODY, SAID END PORTION AND SAID RING, THE SLEEVE MEMBER HAVING ANINNER DIAMETER SUFFICIENTLY GREATER THAN SAID RING TO ACCOMMODATE THEVOLUME OF SAID CABLE OUTER CONDUCTOR WHEN INSERTED THEREWITHIN OVER SAIDRING AND ADAPTED TO BE DEFORMED INWARDLY TO DRIVE SAID CABLE OUTERCONDUCTOR INWARDLY AGAINST SAID RING TO TERMINATE SAID OUTER CONDUCTORTO SAID SLEEVE MEMBER INNER SURFACE, THE SAID SLEEVE MEMBER AND RINGHAVING MATERIAL CHARACTERISTICS RELATIVE TO EACH OTHER WHEREBYDEFORMATION OF SAID SLEEVE TO TERMINATE SAID CABLE OUTER CONDUCTOR TOSAID SLEEVE MEMBER MAY BE ACHIEVED WITHOUT CHANGING THE INNER DIAMETEROF SAID RING.